The proactive Electrical Submersible Pump (ESP) backflush strategy aims to enhance the operation excellence & the efficiency of the ESP pump and increase its lifespan by using a Non-Corrosive Pump (NCP) unit to perform proactive backflush. Instead of waiting for the ESP pump to deteriorate & lose its potential, proactive backflush can reduce the number of failures and avoid production deferment. The deferment associated with frequent trips in wells is around 102,000 bbls of oil yearly from 56 wells in the this field case.
Backflush is often used to remove debris from the wellbore because the high fluid flow rate inside the tubing string enables the recovery of large or dense particles that are difficult or impossible to remove with conventional circulation. A number of ESP wells candidates were selected in one of the clusters in the south of Oman based on the frequency of trips due to debris. The frequency of backflush jobs for each well in every year was also defined based on the frequency of trips for each ESP well.
This paper focuses on presenting the outcomes of proactive ESP backflush and the value generated in the cluster. The definition of selected candidates and the operational method are also detailed.
Initially, we started with the historical performance of the wells in terms of their failure history and wells with multiple backflush or pump stuck cases within a one-year time period. We have listed the wells into five cases based on their historical trip period to define their frequent need to backflush from 2 to 6 times per year.
To ensure successful operational performance, a standard backflush program was created, defining all responsible parties and their rules, along with a communication procedure. Within this program, backflush guidelines were included by the ESP specialist and service NCP unit operator for a number of scenarios, taking care of all different completion types (e.g., ESP with packer or without packer).
There are two main levels that were defined earlier to measure the success rate of the proactive backflush strategy.
Level 1:
Increase ESP run life
Level 2:
Unit to attend job as per shared plan (+/- one day) To perform the job successfully as per the program Spending time per job (max 2 days)
The Level 1 objective was met, and the average ESP run life increased by 40% per well. This also reduced the deferment by 10500 bbl/year per well and resulted in an oil gain of around 9800 bbl/year per well.
Level 2 objectives were also achieved, and a total of 15 jobs were executed per month as planned. Unsuccessful backflushing was observed in wells that had holes in the tubing and were already eroded from sand. The normal (external-upset-end) EUE tubing is not suitable for sandy wells, and hence this problem was not observed in the upgraded tubing to (Glass reinforced epoxy) GRE type.
Overall, the novellaty is discussing a new operation maintenance approach for wells using an ESP (Electric Submersible Pump) system. The new approach is predictive maintenance, which is different from the conventional method of recovery after a well trip. The paper suggests that this new approach has led to an increase in the ESP run life by an average of 40% per well and reduced the frequency of ESP failure, resulting in savings on intervention costs.
